Gear Pump Lubrication Shutoff for Lower Parasitic Loss
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Solution Overview
Problem
Gear pumps for fuel delivery in jet engines face inefficiencies due to parasitic losses from pressurized lubrication, leading to oversizing and reduced operational life, especially at low load conditions like the windmill condition, where lubrication is not needed.
Innovation Solution
A gear pump system with pressure relief valves that automatically shut off lubrication flow at low pressures, allowing for smaller pump designs and extended operational life by minimizing parasitic losses, while maintaining full flow capability at high loads and incorporating redundancy for reliable lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressurized lubrication is provided to the bearing shaft interface at all operating conditions, then the bearing lubrication is adequate, but parasitic losses increase and pump efficiency decreases
Solution Approach 1:
The lubrication system transitions from a static continuous supply to a dynamic conditional supply based on operating parameters. The control system monitors pump pressure and rotational speed, automatically activating or deactivating the lubrication flow paths according to actual operating conditions, thereby eliminating unnecessary parasitic losses while ensuring lubrication when needed
Solution Approach 2:
The system changes the operational parameters of the lubrication system based on pump operating conditions. By monitoring pressure and speed parameters, the system adjusts the lubrication flow state (active/inactive) to match the actual lubrication requirements, optimizing the balance between reliability and energy efficiency
2Reliability
If the pump is oversized to provide sufficient lubrication at all conditions, then lubrication is guaranteed, but the pump size and cost increase
Solution Approach 1:
The pump system incorporates dynamic control of lubrication flow based on operating conditions. By automatically activating lubrication only when pressure and speed thresholds are met, the system allows for a more compact pump design that wouldn't be required if continuous oversized lubrication capacity were mandated for all conditions
3Reliability
If lubrication flow is maintained at low load conditions, then bearing protection is continuous, but operational efficiency decreases
Solution Approach 1:
The lubrication system operates periodically rather than continuously, activating only during high-load conditions that generate sufficient pressure to open the flow paths. During low-load periods, the lubrication flow is deactivated, eliminating parasitic losses while maintaining bearing protection when actually needed
Solution Approach 2:
The system uses the pump's own operating parameters (pressure and speed) to automatically control its lubrication function. The high-pressure fuel environment self-activates the lubrication flow paths when needed, and the system deactivates automatically when pressure drops, requiring no external control intervention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces parasitic losses, enabling smaller pumps with extended operational life, reduced overhaul frequency, and optimized performance across various operating conditions without extensive redesign or hardware replacement.
Implementation Method 1
when the pressure of the fluid in the pump exceeds a threshold pressure, flow paths within the pump automatically open and allow fluid in the pump to flow to a shaft bearing interface. When the pressure of the fluid in the pump is lower than a threshold pressure, the certain flow paths within the pump are closed
Data Source
AI summary
A gear pump that selectively directs lubrication to certain components within the pump. A system and method of retrofitting existing pumps to improve their longevity in the field. The system and method provides a clean, simple, efficient, and elegant improvement to current gear pump fuel delivery systems.